Set early season 1.
If you asked Leopold Fitz what was on his mind lately the answer would not be maths equations, or a new invention, or even anything S.H.I.E.L.D related. No it would be cherries. Yes, you heard that right. Of all the things his level of intelligence could be occupied it was simple, ordinary, baffling fleshy drup.
See, the thing was that Jemma seemed to have taken a liking to cherries lately. Now normally the dietary habits of his co-worker would not bother Fitz, it would not even be noticed, but no Jemma had to pick cherries.
Those small dark, distracting, torturous, incomprehensible and he suspected evil fruits. There was no logical reason as to why watching Jemma eating cherries should be fascinating.
But, alas Fitz sat uncharacteristically quiet as Jemma bit another cherry. The fruit burst as her teeth pierced its flesh, and a small trail of red juice trickled down her bottom lip. Her pink tongue darted out licking away the juice leaving no evidence of the conniving fruit. She spat out the seed in her hand, before dropping it in the bin and moving on to the next.
Fitz watched the process over and over, each time just as enthralled. Jemma mistaking his gaze kindly offered him some. It didn't taste special. At least not as great Jemma made it seem.
So yes, you see Fitz had a problem. Night and day; during his spare time and at work; his thoughts where pre-occupied with, well you know.
And it seemed to be just Jemma's cherries. He had discretely tested it on Coulson, Ward, even May and Skye to better understand why cherries as of late seemed to make his blood race slightly faster. But, it didn't have the same effect. They were not Jemma's cherries. Not even close.
After torturous months spent Fitz had given up in his attempt to understand. Jemma's cherries would have to forever remain and anomaly to him. So time passed and missions went by.
They were in the bus as was usual for the team during their off duty hours (It was a tradition Skye had started). They usually talked, and drank and bonded as a team. Tonight's topic revolved around the worst mission or opponent each team member had faced. It was Fitz's turn.
"Cherries." He answered without missing a beat. A round of confused faces stared at him. "I don't like cherries." He explained.
Jemma frowned. "That's a lie Fitz. You love cherries." Of course she was eating the aforementioned fruit; she even offered him some to prove her point.
"You're right. I do love them." He said, taking the fruit.
It was the truth.
Jemma smiled brightly at him and the rest of the team shrugged and went back to conversing.
He could live with it he supposed. With not knowing... why? After all they were just cherries he mused.
At some point during the evening he noticed Skye stealing some of Jemma's cherries and offered her some pineapple in return. Jemma happily picked up a piece of yellow cube shaped fruit and plopped it in her mouth chewing tenderly, and of course licking her pink lips after.
Goddammit! Fitz realised. It wasn't just cherries anymore. It was spreading.